**Core Concept**
Lactose intolerance is a common condition where individuals are unable to digest lactose, a sugar found in dairy products, due to a deficiency of the enzyme lactase in the small intestine. This enzyme is responsible for breaking down lactose into glucose and galactose, which can then be absorbed by the body.

**Why the Correct Answer is Right**
The correct answer is lactase enzyme. Lactase is a glycosidase enzyme that breaks down lactose into glucose and galactose. In individuals with lactose intolerance, the small intestine does not produce enough lactase enzyme, leading to undigested lactose in the colon. This results in the production of gas, including nitrogen, oxygen, carbon dioxide, and hydrogen, which causes bloating, discomfort, and diarrhea. The undigested lactose is fermented by bacteria in the colon, producing short-chain fatty acids and gas.

**Why Each Wrong Option is Incorrect**
**Option A:** Amylase is an enzyme that breaks down starch into maltose, not lactose. It is not relevant to the symptoms described.
**Option B:** Lipase is an enzyme that breaks down fats into fatty acids and glycerol. It does not affect the digestion of lactose or the symptoms described.
**Option C:** Trypsin is an enzyme that breaks down proteins into peptides and amino acids. It is not involved in the digestion of lactose.
**Option D:** No option was provided for this answer. Please provide a correct option for this question.

**Clinical Pearl / High-Yield Fact**
Lactose intolerance is a common condition that affects approximately 65% of the world's population. It is more prevalent in individuals of African, Asian, and Native American descent.

**Correct Answer:** B. Lipase is an enzyme that breaks down fats into fatty acids and glycerol. It does not affect the digestion of lactose or the symptoms described.